Li Rui, Dozmorov Mikhail, Hellberg Fredrik, Tian Ye, Jilderos Barbro, Wigström Holger
Department of Medical Biophysics, Göteborg University, Box 433, SE 405 30 Göteborg, Sweden.
Neurosci Lett. 2004 Mar 4;357(2):87-90. doi: 10.1016/j.neulet.2003.11.004.
The involvement of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) vs. N-methyl-d-aspartate (NMDA) receptor mediated changes in NMDA-induced long-term depression (LTD) was assessed by monitoring isolated AMPA, isolated NMDA and composite field excitatory postsynaptic potentials (EPSP) in the CA1 area of acute rat hippocampal slices. Application of NMDA (20-50 microM) for 3-5 min led to LTD of both AMPA and NMDA receptor mediated EPSPs with near equal changes of the responses. However, AMPA EPSPs displayed a faster initial recovery than NMDA EPSPs. In addition, during the first 15-25 min after NMDA application, there was a superimposed potentiation of the later, but not early, part of AMPA EPSPs, implying a prolongation of waveform. In contrast, the NMDA EPSP waveform remained unaltered throughout the experiments. While it has been maintained that NMDA-induced depression is equivalent to stimulus-induced LTD, our results reveal additional complexity, suggesting a multitude of changes, most likely at the postsynaptic receptor level.
通过监测急性大鼠海马切片CA1区分离的α-氨基-3-羟基-5-甲基-4-异恶唑丙酸（AMPA）、分离的N-甲基-D-天冬氨酸（NMDA）和复合场兴奋性突触后电位（EPSP），评估了AMPA与NMDA受体介导的NMDA诱导的长时程抑制（LTD）变化。应用NMDA（20-50微摩尔）3-5分钟导致AMPA和NMDA受体介导的EPSP出现LTD，且反应变化几乎相等。然而，AMPA EPSP的初始恢复速度比NMDA EPSP快。此外，在应用NMDA后的最初15-25分钟内，AMPA EPSP后期部分（而非早期部分）出现叠加增强，这意味着波形延长。相比之下，NMDA EPSP波形在整个实验过程中保持不变。虽然一直认为NMDA诱导的抑制等同于刺激诱导的LTD，但我们的结果揭示了额外的复杂性，表明存在多种变化，最有可能发生在突触后受体水平。
